Node Mailer

Mailer.js

const mailer = require('nodemailer');
const validator = require('validator');

class Email {

  constructor() {
    this.config = {
      host: 'host',
      port: 465,
      secure: true,
      auth: {
        user: 'mailer@domain.com',
        pass: 'pass'
      }
    };
    this.message = {
      to: 'info@domain.com',
      from: this.config.auth.user
    };
  }

  init() {
    return new Promise((resolve, reject) => {
      this.transporter = mailer.createTransport(this.config);
      this.transporter.verify(function(err){
        if (err) {
          reject(err);
        } else {
          resolve();
        }
      });
    });
  }
  
  validateInput(msg) {
    return new Promise((resolve, reject)=>{
      let errors = {found: false, fields: {}};
      for (const key in msg) {
        msg[key] = msg[key].trim();
        if (key == 'email') {
          if (!validator.isEmail(msg[key])) {
            errors.found = true;
            errors.fields[key] = 'Please enter a valid email address';
          }
        }
        if (!msg[key]) {
          errors.found = true;
          errors.fields[key] = 'This field is required';
        }
      } 
      if (errors.found) {
        reject(errors.fields);
      } else {
        resolve();
      }
    });

  }

  createMessage (msg) {
    return new Promise((resolve, reject)=>{
      this.validateInput(msg).then(()=>{
        this.message.subject = `New website message from ${msg.firstname}`;
        this.message.text = 
        `${msg.firstname} ${msg.lastname} sent you a message from domain.com\nContact Email: ${msg.email}\n\nMessage:\n\n${msg.message}`;
        resolve();
      }).catch((errors)=>{
        reject(errors);
      });
    });
  }

  send (msg) {
    return new Promise((resolve, reject)=>{
      this.init().then(() => {
        this.createMessage(msg).then(()=>{
          this.transporter.sendMail(this.message, (err)=>{
            if (err) {
              reject(err);
            } else {
              resolve();
            }
          });
        }).catch((err)=>{
          reject(err);
        });
      }).catch((err) => {
        reject(err);
      });
    });
  }
}

module.exports = new Email();